Patent GB-677269-A (GB)
Title: Improvements in or relating to internal combustion engine power plants
IPC: B61C9/14
Filed: 1949-11-14
Abstract: 677,269. Driving gear; power plant. FELL DEVELOPMENTS, Ltd., and FELL, L. F. R. Nov. 14, 1949, No. 29061/49. Addition to 628,448. Class 7(ii) [Also in Group XXXI] In a power unit as claimed in claim 1 of the parent Specification means are provided for driving the planet carrier of the differential gear at different torque ratios by the respective main engines, the invention also includes power plants as claimed in the parent Specification comprising twc power units each as claimed in claim 1 of the parent Specification. The planet carrier of the differential gear of each unit being arranged tc drive a sun wheel of a fur-  ther differential gear the planet carrier of which is adapted to drive the driven mechanism. Means are provided for driving the planet carrier of at least one of the differential gears at different torque ratios by the respective main engines or power units which drive the planet carrier. The latter means may be constituted by the sun wheels of the differential gear themselves an assymmetric differential gear of a type known per se being used in which the sun wheels are of different diameters. Figs. 1 and 2 show respectively an elevation and a plan of a locomotive powered by four compression ignition engines 1a, 1b, 1c, 1d. The engines drive the sun wheels of two primary differential gears 12x, 12y, Fig. 3, through shafts 4a, 4b, 4c and 4d, Fig. 2, variable filling fluid couplings 2a, 2b, 2c, 2d and shafts 5a, 5b, 5c, 5d respectively. The numerals 12x and 12y also denote the planet carriers of the primary differential gears the sun and planet wheels of these gears not being indicated in the figures. The planet carriers 12x, 12y respectively drive the sun wheels of a secondary differential gear of which the planet carrier 16 transmits its drive to the locomotive wheels through the medium of a gear 17 and a reversible transmission gear 18, Fig. 1. The primary and secondary differential gears and the transmission gear are housed in a gear box 3 Mounted on this gear box are two auxiliary compression ignition internal-combustion engines 6x, 6y. These engines drive blowers 7x, 7y. Each of the sun wheels of the primary differential gears is provided with a unidirectional device 9a, 9b, 9c, 9d. The device 9a comprises a self-sliding synchro coupling and a friction clutch 21a. The devices 9b, 9c, 9d do not include a release clutch. The unidirectional devices and release clutch are fully described in Specification 636,808. The plant described is similar to that of the parent Specification but the gear ratios are varied. The object is to obtain the requisite tractive effort speed relationship at the high speed and of the running speed range but to obtain a greater tractive effort at starting and low speeds. In one embodiment suitable for a fast passenger locomotive the primary to secondary gear ratio from the planet carrier 12x to the shaft 15x is equal to 1.25 and that from the planet carrier 12y to the shaft 15y .825. The full operation of the plant including the order of starting of the engines is described. There is some sacrifice of tractive effort at intermediate speeds but this is not of importance in a fast passenger locomotive. Instead of varying the gear ratio at the primary to secondary stage it can be varied at the engine to primary differential stage. Alternatively the engine to primary gear ratios of three engines could be made different from that of the fourth. Again the engine to primary gear ratios of engines 1a and 1c can be different from those of the engines 1b and 1d. The invention is also applicable to plants comprising more than two units. Each main engine is provided with a governor (not shown) which is arranged to control the fuel injection of the engine so that the torque decreases from a maximum value as the engine speed increases. Over-riding the automatic action of the governors are manual controls (also not shown) which enable the main engines to be brought separately from idling speed to maximum torque, these controls at the same time causing the filling of the fluid coupling of the associated engine. The main governors are described in Specification 661,280 referred to, and the control system in Specification 641,873 also referred to. The way in which the desired gear ratios are calculated is described in the Specification.